A reliable method for laboratory testing of candidate materials for use in total joint replacements is essential to prevent the type of disasters that have occurred in the past when unproven materials have been introduced into patients. The multi-channel screening device and test protocol developed in the first two years of that project have been used to evaluate a variety of candidate materials with greater accuracy and reliability than has been previously possible. The test method used to date has involved adhesive-abrasive testing of materials in a flat-on-flat configuration, an analog of conforming-tupe total joints. A main objective of this project will be to expand the wear model to include round-on-flat testing as an analog for certain low-conformity joints. Both wear models then will be employed to evaluate high priority candidate materials under conditions that accurately simulate the intended in-vivo application. Evaluation will include testing of new high strength metal alloys (titanium 6-4, FHS cobalt chrome, Endocast cobalt chrome), ceramics (Alumina, Sialon, Macor) and polymeric materials (compression moulded UHMW polyethylene, Poly II carbon fiber reinforced polyethylene and Delrin 150 polyacetal), with in-depth correlation of wear properties to critical test parameters. Emphasis will also be given to collaboration with other wear study groups in defining standard wear test criteria (ASTM, BSI, ISO).